Medical device delivery catheter

ABSTRACT

Apparatus for delivering a medical device to a location in a patient&#39;s body includes an elongate catheter body having a proximal end and a distal end, a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device, and at least one distal actuator coupled with at least one of the pod and the medical device. The distal actuator is adapted to promote opening of the pod. A method involves advancing a pod at the distal end of an elongate catheter to the location within the body and activating an actuator coupled with the pod and/or the medical device to cause the pod to open. Opening the pod releases the medical device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. Nos.:10/671,191 filed Sep. 24, 2003; 10/833,950 filed Apr. 27, 2004; and10/915,716 filed Aug. 9, 2004, the full disclosures of which are allhereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to medical devices and methods.More specifically, the invention relates to catheter devices and methodsfor delivering a medical device to a location within a patient's body.

One of the most pervasive trends in modern medicine and surgery is thedevelopment of devices and methods for performing minimally invasiveprocedures. For example, balloon angioplasty and stent placement aretechniques that were developed as alternatives to open heart, coronaryartery bypass procedures. Arthoscopic surgical procedures have beendeveloped in orthopedics for performing various surgical procedures onthe knee, shoulder and other joints through small incisions, thusavoiding traditional, open surgical techniques. Laparoscopic surgicalprocedures have been developed for gall bladder removal and otherintra-abdominal surgeries, to reduce trauma and speed recovery time byrequiring only small incisions and minimal abdominal wall trauma.Developments in the minimally invasive arena have even evolved towardrobotic surgical systems, such as the da Vinci® Surgical System providedby Intuitive Surgical, Inc. (Sunnyvale, Calif.), which allows a surgeonto remotely perform operations ranging from prostate or gall bladderremoval to coronary bypass. Hundreds, if not thousands, of new minimallyinvasive techniques are still being developed. For example, a number ofestablished and start-up medical device companies are developingtechniques for repairing or replacing heart valves, ablating portions ofthe heart to treat arrhythmias, and performing other cardiac proceduresusing catheter-based devices.

Other examples of a minimally invasive procedures, devices and systemsare described in U.S. patent application Ser. Nos.: 10/671,191,10/833,950 and 10/915,716, which were incorporated by referenceimmediately above. Generally, these methods and devices involve placinga device in a patient's stomach (and sometimes placing a portion of thedevice across the pyloric valve of the stomach in the duodenum) to treator ameliorate obesity and/or to perform any of a number of otherfunctions, such as to help treat other gastrointestinal disorders.

Many of the newly developed minimally invasive techniques, and many thatwill be developed in the future, involve using a catheter device todeliver a therapy within a patient's body. Some techniques, such asplacing stents in a coronary artery to prop open the artery, involvedelivering a medical device (in this case a stent) from the distal endof the catheter. In another example, a device may be placed into thestomach and/or the duodenum via a catheter advanced through thepatient's esophagus. In many cases, delivering medical devices tolocations within the body using a long, flexible catheter may bedifficult or awkward. For example, it may be difficult to sufficientlycontrol advancement of a long, flexible, low-profile catheter toposition a distally-housed medical device in a desired location in thebody. Even once the distal end of the catheter is advanced to a desiredposition, it may be difficult to release the medical device from thecatheter in precisely the desired location and orientation. Releasingthe device may even damage the device and/or nearby delicate humantissue, in some cases.

For example, delivering a medical device via an elongate catheter ofteninvolves sliding the device out of the catheter. Friction betweensliding surfaces of the medical device and the delivery cathetercomplicates delivery of the device, especially when the catheter iscurved to follow a tortuous pathway, such as a coronary blood vessel. Inthe case of stent delivery, for example, stent delivery from the distalend of a delivery catheter typically involves pushing the stent out ofthe catheter and/or retracting the catheter proximally relative to thestent, while holding the stent in place, all actions which may damagethe stent. Furthermore, a stent is compressed or collapsed to fit withinthe catheter, thus storing energy in the stent. When the stent isreleased, the stored energy may often cause it to propel forward to anundesired location. Additionally, such a delivery catheter requires apusher device for pushing the stent out or holding it stable while aportion of the catheter is retracted and/or a retractable sheath orsleeve, both of which complicate manufacturing of the delivery deviceand necessitate a larger delivery device profile. Catheter-baseddelivery of other medial devices to various locations in the body, suchas placing a device in the stomach, pyloric valve and/or duodenum, mayface similar challenges.

Therefore, a need exists for effective, minimally-invasive ornon-invasive devices and methods for delivering medical devices within apatient's body. Ideally, such devices and methods would be relativelyeasy to use and allow for atraumatic delivery of a medical device to adesired location without damaging the medical device or the deliverydevice. Also ideally, such delivery devices would be relativelylow-profile and allow for precise device placement at the desiredlocation in the body. At least some of these objectives will be met bythe present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention provides apparatus, systems and methods fordelivering a medical device to a location in a patient's body. In oneaspect of the present invention, apparatus for delivering a medicaldevice to a location within a patient's body includes an elongatecatheter body having a proximal end and a distal end, a pod coupled withthe distal end of the catheter body and adapted to house the medicaldevice during delivery to the location and to open to release themedical device, and at least one distal actuator coupled with at leastone of the pod and the medical device, the distal actuator adapted topromote opening of the pod.

In some embodiments, the pod comprises a material disposed over themedical device, and the material is adapted to tear or peel to open thepod. For example, such a material may be either resilient or rigid invarious embodiments, such as but not limited to silicone, polyisoprene,polyimide, polyurethane, polyolefin, polyethylene, nylon, latex,neoprene, stainless steel, nitinol, ceramic, Teflon, a biodegradablematerial, composites or the like. In some embodiments, the materialcomprises a shape-memory material adapted to curl inward after thematerial is torn or peeled. Alternatively, the material may include atleast one set of perforations or slits to promote tearing or peeling ofthe material. The perforations may be disposed along the pod in anysuitable configuration, such as in a straight line(s) parallel to a longaxis of the pod, straight line(s) circumferential about andperpendicular to the long axis of the pod, spiral line(s), wavy line(s)or lines forming an open-mouth shape. In yet another embodiment, thematerial includes a plurality of apertures disposed along opposite ends,and the apparatus further includes a cord for passing through theapertures to maintain the material over the medical device. Removing thecord causes the pod to open. Alternatively, the material may include atleast one structurally weaker portion, relative to the rest of thematerial, to promote tearing or peeling of the material. In still otherembodiments, the material includes at least one zip-lock member along atleast part of its length, the zip-lock member adapted to unzip from aclosed, locked configuration to an open configuration.

In some embodiments, the distal actuator is adapted to cut the material,and the actuator may include any suitable cutter, such as one or moreblades, rip cords, wires, threads, wedges, other cutting members orzippers. In other embodiments, the distal actuator comprises a pressureinput member for introducing positive pressure into the pod to cause thematerial to burst. Alternatively, the distal actuator may comprise aninflation device coupled with the medical device for inflating themedical device to cause the device to expand and rupture the material.

In some embodiments, the apparatus further includes a retractable innershaft extending axially through the housing. The medical device includesat least one lumen to allow the medical device to reside over the innershaft during delivery, such that retracting the inner shaft releases atleast part of the medical device. For example, in some embodiments, theretractable shaft extends beyond a distal end of the pod, and retractingthe shaft releases a distal portion of the medical device, while openingthe pod releases a proximal portion of the medical device.

In an alternative embodiment, the pod comprises at least two opposedhousing members for releasably housing the medical device and at leastone hinge for movably coupling the housing members. The housing membersare adapted to move about the hinge(s) to cause the pod to open. Thehousing members, for example, may comprise a material such as but notlimited to a polymer, a ceramic, a metal, a composite or a biologicalmaterial. In various embodiments, the hinge may be a flexible materialhinge, a living hinge, a pin joint, a universal joint or any other hingeor joint. In some embodiments, at least part of each housing membercomprises a shape-memory material, a super-elastic material or a springloaded material, and the housing members are preformed to move away fromone another when released from constraint. In some embodiments, thedistal actuator is adapted to releasably hold the pod in a closedconfiguration and, upon activation, to release the pod to allow it toassume the open configuration. Such distal actuators may include, forexample, a ring, a retractable sleeve, a tearable sleeve, a pin or aclamp.

Some embodiments of the apparatus further include at least one springdisposed between the housing members to urge them apart. The distalactuator may comprise at least one movable holder disposed about thehousing members, and the holder is movable from a first position to holdthe housing members together to a second position to allow the housingmembers to move apart. Optionally, the holder may be movable from thesecond position to the first position to move the housing members backtogether. In some embodiments, the holder comprises at least one ringdisposed around the housing members. The ring in the first position isdisposed near a distal end of the pod and the ring in the secondposition is disposed near a proximal end of the pod. Alternatively, theholder may comprise a sleeve movably disposed over the housing members.In some embodiments, the actuator further comprises a wedge for urgingthe housing members apart when the holder is moved from the first to thesecond position.

Additional features may also be included. For example, the pod mayinclude at least one radiopaque marker or material. Various embodimentsmay have pods with different tip configurations. For example, the podmay have an open distal end or a closed distal tip. A tip, in someembodiments, may be a rigid, pointed tip adapted to pierce throughtissue. Alternatively, the tip may be a blunt, atraumatic tip to preventtissue damage during advancement of the pod. In some embodiments, thetip includes flexible nose having at least one aperture or lumen foraccepting a guidewire.

Optionally, the apparatus may also include a movable pusher memberdisposed in the pod to urge the medical device out of the opened pod.For example, the pusher member may include a platform disposed near aproximal end of the pod for contacting and urging the medical device andan elongate shaft coupled with the platform and extending through thecatheter body to its proximal end to allow a user to advance and retractthe platform. In another embodiment, the pusher member comprises aspring-loaded platform disposed near a proximal end of the pod, theplatform adapted to urge the medical device out of the pod upon releasefrom constraint. In some embodiments, the platform is automaticallyreleased from constraint when the pod opens. In other embodiments, theplatform is released from constraint by the user. The apparatus may alsoinclude a safety mechanism releasably coupled with the platform toprevent the platform from advancing prematurely.

Some embodiments of the device further include at least one supportmember disposed along at least part of a length of the pod for reducingbending of the pod. In one embodiment, for example, multiple supportmembers are disposed along an inner surface of the pod. Such supportmembers may comprise silicone or any other suitable material. Theapparatus may also include a guidewire lumen disposed along at leastpart of the pod. Such a guidewire lumen may be disposed along an outersurface of the pod or an inner surface of the pod. In some embodiments,the guidewire lumen extends onto at least part of the catheter body.Optionally, an additional guidewire lumen may be disposed along at leastpart of the medical device.

In some embodiments, the device includes at least one proximal actuatorcoupled with the distal actuator to allow a user to activate the distalactuator. Such a proximal actuator may include, for example, a trigger,a pull cord, a button, a dial, a slide actuator or the like. In someembodiments, the proximal actuator is coupled with the distal actuatorvia at least one of a shaft and a cord extending through a lumen of thecatheter body. Alternatively, the proximal actuator may be coupled withthe distal actuator via an electrical connection. Optionally, thecatheter body may include a series of depth markings on its outersurface to indicate to a user how far the pod is inserted within thepatient's body.

In one embodiment, the medical device is adapted to reside in a stomachand intermittently contact a pyloric valve. For example, one deviceincludes a distal portion for residing in a duodenum, a proximal portionfor residing in the stomach, and an elongate connecting portion forconnecting the distal portion with the proximal portion and adapted toextend across the pyloric valve. In some embodiments, the deliveryapparatus is adapted to release the distal portion in the duodenum andthen release the proximal portion in the stomach. Also in someembodiments, the medical device is adapted to slow the passage of foodfrom through the pyloric valve to help treat obesity. Alternatively, oradditionally, the medical device may adapted to house or anchor a secondmedical device disposed in the stomach, a small intestine or both toperform a function within the stomach and/or small intestine.

In another aspect of the present invention, apparatus for delivering amedical device to a location in a patient's body includes an elongatecatheter body having a proximal end and a distal end, and a pod coupledwith the distal end of the catheter body and adapted to house themedical device during delivery to the location and to open to releasethe medical device. The pod is adapted to automatically open after beingpositioned in the location. In one embodiment, the pod comprises amaterial disposed over the medical device, and at least part of thematerial is biodegradable. Optionally, the pod may further include atleast two opposed housing members disposed within the material, whereinthe housing members automatically move apart to cause the pod to openwhen the material at least partially degrades. In some embodiments, thelocation is a stomach of the patient, and at least part of the materialis rapidly biodegradable in the stomach. In alternative embodiments, thepod comprises a material disposed over the medical device, and at leastpart of the material degrades upon reaching a temperature present at adesired delivery location.

In another aspect of the present invention, a system for delivering amedical device to a location in a patient's body includes an elongatecatheter body having a proximal end and a distal end, a pod coupled withthe distal end of the catheter body and adapted to house the medicaldevice during delivery to the location and to open to release themedical device, at least one distal actuator coupled with at least oneof the pod and the medical device, the distal actuator adapted topromote opening of the pod, and a medical device releasably housedwithin the pod. In some embodiments, the device includes a distalportion for residing in a duodenum, a proximal portion for residing inthe stomach, and an elongate connecting portion for connecting thedistal portion with the proximal portion and adapted to extend acrossthe pyloric valve. The delivery apparatus may be adapted to release thedistal portion in the duodenum and then release the proximal portion inthe stomach. In one embodiment, the medical device is adapted to residein a stomach and intermittently contact the pyloric valve. Such amedical device may be adapted to slow the passage of food from throughthe pyloric valve to help treat obesity. Alternatively, or additionally,the medical device may be adapted to house or anchor a second medicaldevice disposed in the stomach, a small intestine or both to perform afunction within the stomach and/or small intestine. In one embodiment,the system further includes a tether coupling the medical device to atleast one of the catheter body and the pod. Removing the catheter fromthe patient removes the medical device from the patient.

In yet another aspect of the present invention, a method for deliveringa medical device to a location in a patient's body includes advancing apod at the distal end of an elongate catheter to the location within thebody and activating an actuator coupled with at least one of the pod andthe medical device to cause the pod to open. Opening the pod releasesthe medical device. In some embodiments, at least a distal portion ofthe pod is advanced across the patient's pyloric valve, such that whenthe pod is opened, a distal portion of the medical device resides in thepatient's duodenum, a proximal portion of the device resides in thepatient's stomach, and an elongate connecting portion extends betweenthe distal and proximal portions, across the pyloric valve.

In some embodiments, activating the actuator comprises at least one oftearing, peeling and cutting the pod. For example, in variousembodiments the pod may be torn, peeled or cut along one or moreperforated lines or lines of structural weakness. Activating theactuator, in one embodiment, involves withdrawing a cord from aplurality of apertures in the pod, the cord adapted to hold the podtogether around the medical device. Alternatively, activating theactuator may involve retracting a sleeve disposed over shape-memory,super-elastic or spring loaded housing. In another embodiment,activating the actuator comprises retracting a ring disposed over two ormore housing members of the pod, wherein the housing membersautomatically move apart when released from constraint within the ring.In yet another alternative, activating the actuator may involvepressurizing the pod to cause it to burst open. Or, activating theactuator may involve inflating the medical device to cause it to expandand thus burst open the pod.

In some embodiments, the method further comprises urging the medicaldevice out of the opened pod with a pusher member. The method may alsoinclude retracting an inner shaft extending through a longitudinal lumenof the medical device, wherein retracting the shaft releases at least aportion of the device. In one embodiment, the released portion of themedical device comprises a distal shape-memory portion configured tochange from a straight configuration when disposed over the shaft to anon-linear configuration when released from the shaft. In someembodiments, the pod is advanced over a guidewire extending through aguidewire lumen on the pod.

These and other aspects and embodiments of the invention are describedin greater detail below, with reference to the attached drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a medical device delivery catheter,according to one embodiment of the present invention.

FIGS. 2A and 2B are side views of a distal end of a medical devicedelivery catheter in closed (FIG. 2A) and open (FIG. 2B) configurations,according to one embodiment of the present invention.

FIGS. 3A-3C are side views of a distal end of a medical device deliverycatheter having a pod and a retractable inner shaft, the figuresillustrating a method of medical device delivery, according to oneembodiment of the present invention.

FIG. 4 is a side view of a distal end of a medical device deliverycatheter having a pod with a stepped diameter, according to oneembodiment of the present invention.

FIG. 5 is a side view of a distal end of a medical device deliverycatheter having a pod with reinforcing side-wall members, according toone embodiment of the present invention.

FIG. 6 is a perspective view of a portion of a material for forming apod, illustrating one method for coupling edges of the pod materialtogether, according to one embodiment of the present invention.

FIGS. 7A-7C are side views of a peel-away distal pod of a medical devicedelivery catheter, illustrating a method for peeling the pod, accordingto one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In various embodiments, a medical device delivery catheter may be usedto delivery any of a number of medical devices in any of a number oflocations in a human body. For example, one embodiment may be used todeliver stents in an a coronary artery, another embodiment may deliverstents in peripheral blood vessels, other embodiments may be used todeliver various devices within the heart, orthopedic embodiments may beused to deliver devices within various joints, and the like. In thedescription that follows and in the attached figures, variousembodiments of a medical device delivery catheter are adapted fordelivering a device in a patient's stomach, with the device in somecases crossing the pyloric valve and extending into the duodenum.Examples of such devices are described in U.S. patent application Ser.Nos.: 10/671,191, 10/833,950 and 10/915,716, which are assigned to theassignee of the present invention and which were previously incorporatedby reference. Alternative embodiments, however, may be used fordelivering any other suitable device to any of a number of locations inthe body.

That being said, and referring now to FIG. 1, in one embodiment, amedical device delivery catheter 10 includes a catheter body 12 with apeel-away pod 14 at its distal end. A medical device 18, in thisembodiment a device for placing in a stomach, is housed within peel-awaypod 14. Peel-away pod 14 includes perforations 20 and a cutter 22. Apull cord 24 is attached to cutter 22 and extends through catheter body12 to exit proximally and attach to a pull ring 25. Pulling proximallyon pull ring 25 causes cutter 22 to move proximally along perforations20, thus opening peel-away pod 14 to release medical device 18.

In various embodiments, peel-away pod 14 may cover all or only part ofmedical device 18 during delivery. Pod 14 may generally be made of anyof a number of different materials or combinations of materials.Typically, peel-away pod 14 is made of a resilient or elastomericmaterial that is positioned, sometimes stretched, over medical device18. Such resilient materials may include, for example, silicone,polyisoprene, polyimide, polyurethane, polyolefin or the like. Inalternative embodiments, peel-away pod 14 may be made of a rigidmaterial such as but not limited to polyethylene, nylon, stainlesssteel, nitinol, ceramic, Teflon or a composite material, withperforations 20, slits, holes or the like allowing pod 14 to break ortear apart. Perforations 20 extend along the entire length of pod 14 oronly part of pod 14. They may also be disposed along pod 14 in anysuitable configuration or pattern, such as in one or more longitudinallines, one or more circumferential lines, one or more spiral lines, anopen mouth configuration, irregular or asymmetrical patterns, or thelike. In yet other embodiments, one or more lines of structuralweakness, other than perforations 20, may be built into peel-away pod14, such as lines of thinner or structurally weaker material, anon-reinforced portion of a pod 14 that is reinforced elsewhere viafibers, bands or the like, or a combination of non-homogeneousmaterials.

In alternative embodiments, all or part of pod 14 may be made of abiodegradable material adapted to dissolve upon positioning within thedesired delivery location, thus releasing medical device 18. Forexample, pod 14 may be made of a material designed to rapidly dissolvewithin the environment of the stomach. Examples of such biodegradablematerials include, but are not limited to, gelatin, wax, starch, lacticacid, sugars, proteins, gum and polyvinyl alcohol. Some non-degradablepods 14 may be made of shape-memory or super-elastic material such thatthey curl or fold inward after they are torn or peeled open to releasemedical device 18. Curling over edges of pod 14 may help preventdamaging contact with tissues during extraction of delivery device 10.

Any of a number of suitable mechanisms may be used to allow pod 14 toopen via tearing, peeling, splitting, or the like. Perforations 20 arebut one example. As shown in FIG. 6, in other embodiments, a podmaterial 26 may have multiple apertures 30 in opposite edges 26 a, 26 b,such that material 26 may be wrapped around a medical device (not shown)and the edges 26 a, 26 b may be attached via a cord 30. (Generally, forthe purposes of this application, the term “cord” shall mean any cord,wire, thread, filament, string or the like.) Cord 30 is wound throughapertures 28 to hold the two edges 26 a, 26 b of material 26 together,thus constraining medical device 18 within material 26. Cord 30 may thenbe withdrawn (solid-tipped arrow) to free edges 26 a, 26 b, thusallowing material 26 to open, and thus releasing the medical device. Invarious embodiments, cord 30 may be sewn through apertures 28 orperforations or wrapped or looped around apertures 28 or perforations.

Returning to FIG. 1, in various embodiments, any suitable cutter 22 orother actuator device for cutting or beginning a tear in peel-away pod14 may be used. For example, cutter 22 may be a blade, cord, wedge, orthe like. In an alternative embodiment, part of medical device 18 itselfmay act as cutter 22, with that part of medical device 18 beingretracted or advanced in such a way as to cut pod 14. Alternatively, azipper may be used to unzip peel-away pod 14. In one embodiment,perforations 20 are replaced with a zip-lock device, which is unzippedto open pod 14.

Cutter 22 is attached to pull cord 24, which extends from cutter 22through catheter body 12 to exit proximally and attach to pull ring 25.In various alternative embodiments, pull ring 25 may be replaced withany other actuator devices, such as but not limited to a slide, trigger,button or the like. Pulling proximally on pull ring 25 moved cutter 22proximally along perforations 20, thus cutting (or “peeling”) pod 14open to release medical device 18.

Pod 14 may include any of a number of different distal endconfigurations. In the embodiment shown, for example, peel-away pod 14has an open distal end, and medical device 18 protrudes out of thedistal end to form a blunt tip. In another embodiment, pod 14 mayinclude a blunt tip that completely surrounds medical device 18. In someembodiments, a the tip of pod 14 may be flexible, to help facilitateadvancement along a guidewire through a tortuous anatomical path. Inanother alternative embodiment, peel-away pod 14 may include a sharp orpointed tip to facilitate piercing through tissue, for example tofacilitate piercing through tough connective tissue to deliver device 18into a joint space.

Referring now to FIGS. 2A and 2B, another embodiment of a medical devicedelivery catheter 40 suitably includes a catheter body 58 and a pod 41,with pod 41 being adapted to house medical device 18. Pod 41 generallyincludes two opposed housing members 42, movably coupled at theirproximal ends by a hinge 56 to enable pod 41 to open like a clam shell(FIG. 2B). Attached to one of housing members 42 is a guidewire tube 44to allow catheter 40 to be advanced over a guidewire 46. Disposed overthe distal end of pod 41 in FIG. 2A is a ring 48, coupled with a pullcord 50. A movable inner shaft 54 extends through catheter body 58 andis attached distally to a platform 52 for helping push medical device 18out of the opened pod 41 (FIG. 2B).

Various alternative embodiments of catheter 40 may include a number ofvariations. For example, guidewire tube 44, in some embodiments, may bepositioned on the inside of pod 41, may extend onto catheter body 58 ormay be disposed entirely on catheter body 58 and not on pod 41.Similarly, pull cord 50 may be disposed inside pod 41 and catheter body58 in some embodiments. Inner shaft 54 and platform 52 are optionalfeatures, which are not necessarily included in all embodiments. In analternative embodiment, platform 52 is attached via a spring to theproximal end of the inside of pod 41, such that platform 52 isspring-loaded and automatically springs forward upon release of medicaldevice 18 from pod 41. Any suitable hinge 56, or multiple hinges, may besubstituted. In alternative embodiments, pod 41 may open by curvingoutward due to shape-memory or spring-loaded materials rather than via ahinge. Other closure devices may also be substituted for ring 48, suchas a closure sleeve, pin, movable clamp or the like. Housings 42 may beeither rigid or flexible and may be made of any suitable material orcombination of materials. In some embodiments, the outer diameter of pod41 is greater than the outer diameter of catheter body 58, as in FIGS.2A and 2B. In alternative embodiments, the outer diameters may be thesame. Thus, various embodiments of medical device delivery catheter 40may have any of a number of different configurations and features,without departing from the scope of the present invention.

In use, delivery catheter 40 is positioned in a desired location fordelivering medical device 18, such as in the stomach and possiblyextending across the pyloric valve into the duodenum. Advancement to adesired location may be facilitated by incorporating one or moreradiopaque markers or materials into catheter 40 and/or by including oneor more depth markings on the outer surface of a proximal portion ofcatheter body 58 to help the user determine how far catheter 40 has beenadvanced into the body. Once pod 41 and medical device 18 are in adesired location, pull cord 50 is pulled proximally by a user at theproximal end of catheter 40, thus causing ring to move proximally downpod 41 (solid-tipped arrows). Medical device 18 is constrained in acompressed configuration within pod 41, such that when ring 48 is movedproximally (FIG. 2B), medical device 18 springs/expands into anunconstrained, expanded configuration, thus pushing apart housingmembers 42, which separate easily due to hinge 56. Medical device 18 isthus released from pod 41. To further urge medical device 18 out of pod41, inner shaft 54 may be advanced by the user to push medical device 18forward with platform 52. Using this method, medical device 18 may beplaced such that a distal portion 21 resides within the duodenum, aconnection portion 19 resides across the pyloric valve, and a proximalportion 17 resides within the stomach. The distal portion 21 andproximal portion 17 are typically the expandable portions constrainedwithin pod 41 when it is closed and that push pod 41 open when ring 48or other constraining device is removed. Once medical device 18 isreleased, housing members 42 close naturally as delivery catheter 40 iswithdrawn from the body.

Referring now to FIGS. 3A-3C, in an alternative embodiment, a medicaldevice delivery catheter 60 suitably includes a catheter body 66, a pod64 attached to the distal end of catheter body 66, and a retractableinner shaft 68, extending through catheter body 66 and pod 64, andbeyond the distal end of pod 64. Pod 64 includes a perforated line 70and a cutter 74. Medical device 62, in this embodiment, includes anexpandable proximal portion 72, and a distal portion 65, which includesa shape memory distal end 65. As shown in FIGS. 3B and 3C, proximalportion 72 includes a central lumen 76, through which inner shaft 68 maypass.

With reference to FIG. 3A, in use, delivery catheter 60 is positionedsuch that pod 64 resides within a patient's stomach S and inner shaft 68with distal portion 65 of medical device 62 extends at least partiallyacross the pyloric valve PV, and sometimes into the duodenum D, asshown. When catheter 60 and device 62 are in a desired location fordeployment, which may be confirmed with one or more radiopaque markingon catheter 60 and/or device 62, and/or with depth markings on the outersurface of catheter body 66, inner shaft is retracted 68 (solid-tippedarrows). As illustrated in FIG. 3B, when inner shaft 68 is removed fromdistal portion 65, shape memory distal end 65 a deforms from itsstraight, undeployed shape to its deployed shape, which in this case isa helical shape. Other shapes, such as a round or elliptical ball-likeshape, an hourglass shape, a curled snail-like shape or the like may beused in alternative embodiments. Distal end 65 a may suitably be made ofany shape-memory, super-elastic material, spring-loaded, or otherresilient material to allow it to move from the undeployed to deployedconfiguration. Generally, distal end 65 a in its deployed configurationis designed to reside within a proximal portion of the duodenum D and toprevent its passage through the pyloric valve PV, back into the stomachS.

To deploy proximal portion 72 of medical device 62, pod 64 is cut (ortorn, split or peeled, in various embodiments) along perforated line 70,using cutter 74. As shown in FIG. 3C, proximal portion 72 expands uponrelease from pod 64, thus assuming its deployed, expanded configuration,which causes it to remain in the stomach S and prevents it from crossingthe pyloric valve PV into the duodenum D. Rotational orientation ofmedical device 62 about the long axis of catheter 60 may often beimportant to achieve a desired delivery. Thus, in some embodiments, theorientation of perforated line 70, and thus the side on which pod 64opens, is configured to achieve a desired, and controlled, rotationalorientation of medical device 62 upon delivery. Delivery catheter 60 maythen be withdrawn, leaving medical device 62 in place within the stomachS, crossing the pyloric valve PV into the duodenum D.

Various embodiments of delivery catheter 60 may include additionalfeatures to enhance and/or facilitate delivery of medical device 62. Forexample, rotational orientation of inner shaft 68 with respect tomedical device 62 may be controlled in some embodiments by “keying”device 62 to shaft 68. The keying function may be achieved by providingcatheter 60 with a non-circular lumen (e.g., square, triangle, slot,etc.) keyed to a non-circular cross-sectional shape of device 62. In analternative embodiment, device 62 may engage shaft 68 via a keyed anchordisposed along the length of device 62 (or in multiple locations). Inone embodiment, an anchor is cast in the distal tip of device 62. Theanchor may have a slot in which shaft 68 engages. In some embodiments,shaft 68 may also include one or more shape-memory or super-elasticmaterials, to counteract the restorative forces of medical device 62 inits constrained configuration.

Referring now to FIG. 4, in one embodiment, a medical device deliverycatheter 80 includes a catheter body 86 and a pod 82, which includes awider proximal portion 82 a, a narrower distal portion 82 b, and astep-off 84 between the two. Pod 82 may open via perforations 88 or, inalternative embodiment, any other suitable means as described above.Distal portion 82 b is configured and sized such that it can be advancedthrough the pyloric valve PV to position its distal end in the duodenumD. Step-off 84 is configured and sized such that it will not movethrough the pyloric valve PV. Thus, pod 82 is configured to allow a userto advance delivery catheter 80 partially through the pyloric valve torelease a medical device 81 in a location spanning the valve. Whendelivery catheter 80 is sufficiently advanced, step-off 84 bumps upagainst the pyloric valve PV, such that the user can feel the abutmentand knows catheter 80 is sufficiently advanced. Medical device 81 isthen deployed in the desired location spanning the valve. In analternative embodiment (not shown) the medical device itself, ratherthan the pod, includes a step-off in diameter to allow partial, but notcomplete, passage through the pyloric valve PV.

In a number of embodiments, and with reference now to FIG. 5, medicaldevice delivery catheter 90 includes a catheter body 94 and a pod 92having one or more support members 96 disposed along its inner wall andone or more sets of perforations 98. Support members 96, for example,may be elongate, curved, horseshoe-shaped or otherwise configured piecesof silicone molded or attached to the wall via adhesive. In alternativeembodiments, support members 96 may be attached with stitching or caseinto pod 92. In still further embodiments, support members 96 may bebiodegradable. Support members 96 are generally configured to helpstabilize pod 92 and prevent it from kinking or bending in an area inwhich a narrower portion of a medical device 91 is disposed. In otherembodiments, support members 96 may be embedded in the wall of pod 92,and may include other materials such as metal.

Referring now to FIGS. 7A-7C, another embodiment of a medical devicedelivery catheter 100 is shown, and a method for opening a pod 102 isillustrated. Pod 102 includes two sets of perforations 104, and a cord106 extends along pod 102 and is attached at its distal end via anattachment member 108. When cord 106 is pulled proximally (solid-tippedarrow), a portion of pod 102 peels away, as shown in FIG. 7B, thusexposing the interior 109 of pod 102. Typically, a medical device (notshown) is housed in interior 109 and is thus released when pod 102 ispeeled. As cord 106 is pulled farther proximally (solid-tipped arrow),pod 102 peels open further, as in FIG. 7C. In various embodiments, pod102 may have any of a number of various perforations, slits, holes, thinmaterial portions or the like to allow for peeling, tearing, cutting orother means for opening pod 102.

Although the above is a complete and accurate description of theinvention, any of a number of variations, additions and the like may bemade to the embodiments described without departing from the scope ofthe invention. For example, devices and methods described above may beused to treat any suitable condition or perform any suitable functionwithin the gastrointestinal tract. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is defined in thefollowing claims.

1. Apparatus for delivering a medical device to a location in a patient's body the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a material disposed over the medical device, the material adapted to tear or peel to open the pod, and wherein the material comprises a shape-memory material adapted to curl inward after the material is torn or peeled.
 2. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a material disposed over the medical device, the material adapted to tear or peel to open the pod, and wherein the material includes a plurality of apertures disposed along opposite ends, the apparatus further comprising a cord for passing through the apertures to maintain the material over the medical device, wherein removing the cord causes the pod to open.
 3. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a material disposed over the medical device, the material adapted to tear or peel to open the pod, and wherein the distal actuator comprises a pressure input member for introducing positive pressure into the pod to cause the material to burst.
 4. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a material disposed over the medical device, the material adapted to tear or peel to open the pod, and wherein the distal actuator comprises an inflation device coupled with the medical device for inflating the medical device to cause the device to expand and rupture the material.
 5. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, further comprising a retractable inner shaft extending axially through the housing, wherein the medical device includes at least one lumen to allow the medical device to reside over the inner shaft during delivery, and wherein retracting the inner shaft releases at least part of the medical device, wherein the retractable shaft extends beyond a distal end of the pod, wherein retracting the shaft releases a distal portion of the medical device, and wherein opening the pod releases a proximal portion of the medical device.
 6. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises: at least two opposed housing members for releasably housing the medical device; and at least one hinge for movably coupling the housing members, wherein the housing members are adapted to move about the hinge(s) to cause the pod to open.
 7. Apparatus as in claim 6, wherein the housing members comprise a material selected from the group consisting of a polymer, a ceramic, a metal, a composite and a biological material.
 8. Apparatus as in claim 6, wherein the hinge is selected from the group consisting of a flexible material hinge, a living hinge, a pin joint and a universal joint.
 9. Apparatus as in claim 6, wherein at least part of each housing member comprises at least one of a shape-memory material, a super-elastic material and a spring loaded material, and wherein the housing members are preformed to move away from one another when released from constraint.
 10. Apparatus as in claim 9, wherein the distal actuator is adapted to releasably hold the pod in a closed configuration and, upon activation, to release the pod to allow it to assume the open configuration.
 11. Apparatus as in claim 10, wherein the distal actuator is selected from the group comprising a ring, a retractable sleeve, a tearable sleeve, a pin and a clamp.
 12. Apparatus as in claim 6, further comprising at least one spring disposed between the housing members to urge them apart.
 13. Apparatus as in claim 6, wherein the distal actuator comprises at least one movable holder disposed about the housing members, wherein the holder is movable from a first position to hold the housing members together to a second position to allow the housing members to move apart.
 14. Apparatus as in claim 13, wherein the holder is movable from the second position to the first position to move the housing members back together.
 15. Apparatus as in claim 13, wherein the actuator further comprises a wedge for urging the housing members apart when the holder is moved from the first to the second position.
 16. Apparatus as in claim 13, wherein the holder comprises at least one ring disposed around the housing members, and wherein the ring in the first position is disposed near a distal end of the pod and the ring in the second position is disposed near a proximal end of the pod.
 17. Apparatus as in claim 13, wherein the holder comprises a sleeve movably disposed over the housing members.
 18. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod includes an open distal end, and wherein a distal end of the medical device extends out of the open distal end of the pod to form a flexible tip.
 19. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a distal tip, and wherein the tip comprises a rigid, pointed tip adapted to pierce through tissue.
 20. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, wherein the pod comprises a distal tip, and wherein the tip comprises a flexible nose having at least one aperture or lumen for accepting a guidewire.
 21. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device; and at least one distal actuator coupled with at least one of the pod and the medical device, the distal actuator adapted to promote opening of the pod, further comprising at least one support member disposed along at least part of a length of the pod for reducing bending of the pod, wherein the at least one support member comprises multiple support members disposed along an inner surface of the pod.
 22. Apparatus as in claim 21, wherein the support members comprise silicone.
 23. Apparatus for delivering a medical device to a location in a patient's body, the apparatus comprising: an elongate catheter body having a proximal end and a distal end; and a pod coupled with the distal end of the catheter body and adapted to house the medical device during delivery to the location and to open to release the medical device, wherein the pod is adapted to automatically open after being positioned in the location, wherein the pod comprises a material disposed over the medical device, and wherein at least part of the material is biodegradable.
 24. Apparatus as in claim 23, the pod further comprising at least two opposed housing members disposed within the material, wherein the housing members automatically move apart to cause the pod to open when the material at least partially degrades.
 25. Apparatus as in claim 23 or 24, wherein the location is a stomach of the patient, and wherein at least part of the material is rapidly biodegradable in the stomach.
 26. Apparatus as in claim 23, wherein the pod comprises a material disposed over the medical device, and wherein at least part of the material degrades upon reaching a temperature present at a desired delivery location. 